Earth-boring tools for forming wellbores in subterranean earth formations may include a plurality of cutting elements secured to a body include, such as, for example, fixed-cutter earth-boring rotary drill bits (also referred to as “drag bits”). Such fixed-cutter bits include a plurality of cutting elements that are fixedly attached to a bit body of the drill bit, conventionally in pockets formed in blades and other exterior portions of the bit body. Other earth-boring tools may include rolling cone earth-boring drill bits, which include a plurality of roller cones attached to bearing pins on legs depending from a bit body. The roller cones may include cutting elements (sometimes called “inserts”) attached to the roller cones, conventionally in pockets formed in the roller cones.
Brazing is widely used to join cutting elements to such earth-boring tools and components of such earth-boring tools by means of a braze material (e.g., a filler material) that melts upon heating and coats the surface of materials being joined, creating a bond upon cooling and solidification of the braze material. A suitable braze material wets the surfaces of the materials being joined and allows the materials to be joined without changing the physical properties of the materials. Braze materials are conventionally selected to melt at a lower temperature than a melting temperature or temperatures of the materials being joined. During a brazing process, heating and cooling of the materials may take place in the open atmosphere or in a controlled atmosphere furnace or vacuum furnace. Braze materials are often based on metals such as Ag, Au, Cu, Ni, Ti, Pd, Pt, Cr, and alloys thereof. Braze base materials may also include fractions of a wide variety of other elements that are added to vary the properties of the resulting alloy. Brazing can be used effectively to join similar or dissimilar materials (e.g., metals to metals, ceramics to ceramics, and metals to ceramics).
Typically, in a brazing process a filler metal or alloy is heated to a melting temperature above 800° F. (427° C.) and distributed between two or more close-fitting parts by direct placement of the filler material between the parts, or drawn into an interface between the parts by capillary action. At the melting temperature of a braze material, the molten braze material interacts with the surfaces of the parts, cooling to form a strong, sealed joint. A brazed joint may thus become a sandwich of different layers, each layer metallurgically linked to one or more adjacent layers.
Brazing cutting elements to an earth-boring tool may cause individual cutting elements to have final orientations that are offset from intended orientations of the cutting elements due to human error in applying the braze, non-uniform application of the braze material, and distortion of the components to which the cutting elements are attached. In addition, brazing may require preheating the body of the earth-boring tool, and application of specialized brazing environments (e.g., controlled atmospheres), which may be expensive, time-consuming, and may potentially warp portions of the bit beyond acceptable tolerances.